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Litmus Test (chemistry)
Litmus is a water-soluble mixture of different dyes extracted from lichens. It is often absorbed onto filter paper to produce one of the oldest forms of pH indicator, used to test materials for acidity. In an acidic medium, blue litmus paper turns red, while in a basic or alkaline medium, red litmus paper turns blue. In short, it is a dye and indicator which is used to place substances on a pH scale. History The word "litmus" comes from the Old Norse word "litmosi" meaning "colour moss" or "colouring moss". The word is attested only in one Mediaeval source, a Norwegian law codex from 1316 in a chapter on customs and excise duties on pelts and furs. About 1300, the Spanish physician Arnaldus de Villa Nova began using litmus to study acids and bases. From the 16th century onwards, the blue dye was extracted from some lichens, especially in the Netherlands. Natural sources Litmus can be found in many different species of lichens. The dyes are extracted from such spec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Roccella Pygmaea
''Roccella'' is a genus of 23 species of lichens in the family Roccellaceae. The genus was circumscribed by Swiss botanist Augustin Pyramus de Candolle in 1805, with '' Roccella fuciformis'' as the type species. Description ''Roccella'' presents a fruticose (shrub-like), thallus that is either erect or (hanging) with sparse branching. The main and terminal , varying in shape from flattened to rounded (), typically measure 2 to 5 mm (up to 10 mm) in thickness and 5 to 15 cm in length. These branches has colours ranging from creamy white-greyish to greyish-brown and have surfaces that are either smooth or wrinkled, with some being sparsely (powdery) or lacking pruina (epruinose). Soredia, reproductive propagules for asexual reproduction, are present in many species within the genus. The of ''Roccella'' lichens is made of hyphae that are arranged in an manner and are about 40 to 70 μm thick. The medulla (the inner layer) is loosely structured above, ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Basicity
In chemistry, there are three definitions in common use of the word "base": ''Arrhenius bases'', ''Brønsted bases'', and ''Lewis bases''. All definitions agree that bases are substances that react with acids, as originally proposed by Guillaume-François Rouelle, G.-F. Rouelle in the mid-18th century. In 1884, Svante Arrhenius proposed that a base is a substance which dissociates in aqueous solution to form hydroxide ions OH−. These ions can react with Hydron (chemistry), hydrogen ions (H+ according to Arrhenius) from the dissociation of acids to form water in an acid–base reaction. A base was therefore a metal hydroxide such as NaOH or Calcium hydroxide, Ca(OH)2. Such aqueous hydroxide solutions were also described by certain characteristic properties. They are slippery to the touch, can taste Taste#Bitterness, bitter and change the color of pH indicators (e.g., turn red litmus paper blue). In water, by altering the self-ionization of water, autoionization Chemical equi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acidity
An acid is a molecule or ion capable of either donating a proton (i.e. hydrogen cation, H+), known as a Brønsted–Lowry acid, or forming a covalent bond with an electron pair, known as a Lewis acid. The first category of acids are the proton donors, or Brønsted–Lowry acids. In the special case of aqueous solutions, proton donors form the hydronium ion H3O+ and are known as Arrhenius acids. Brønsted and Lowry generalized the Arrhenius theory to include non-aqueous solvents. A Brønsted–Lowry or Arrhenius acid usually contains a hydrogen atom bonded to a chemical structure that is still energetically favorable after loss of H+. Aqueous Arrhenius acids have characteristic properties that provide a practical description of an acid. Acids form aqueous solutions with a sour taste, can turn blue litmus red, and react with bases and certain metals (like calcium) to form salts. The word ''acid'' is derived from the Latin , meaning 'sour'. An aqueous solution of an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Base (chemistry)
In chemistry, there are three definitions in common use of the word "base": '' Arrhenius bases'', '' Brønsted bases'', and '' Lewis bases''. All definitions agree that bases are substances that react with acid An acid is a molecule or ion capable of either donating a proton (i.e. Hydron, hydrogen cation, H+), known as a Brønsted–Lowry acid–base theory, Brønsted–Lowry acid, or forming a covalent bond with an electron pair, known as a Lewis ...s, as originally proposed by Guillaume-François Rouelle, G.-F. Rouelle in the mid-18th century. In 1884, Svante Arrhenius proposed that a base is a substance which dissociates in aqueous solution to form hydroxide ions OH−. These ions can react with Hydron (chemistry), hydrogen ions (H+ according to Arrhenius) from the dissociation of acids to form water in an acid–base reaction. A base was therefore a metal hydroxide such as NaOH or Calcium hydroxide, Ca(OH)2. Such aqueous hydroxide solutions were also described by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acid (chemistry)
An acid is a molecule or ion capable of either donating a proton (i.e. hydrogen cation, H+), known as a Brønsted–Lowry acid, or forming a covalent bond with an electron pair, known as a Lewis acid. The first category of acids are the proton donors, or Brønsted–Lowry acids. In the special case of aqueous solutions, proton donors form the hydronium ion H3O+ and are known as Arrhenius acids. Brønsted and Lowry generalized the Arrhenius theory to include non-aqueous solvents. A Brønsted–Lowry or Arrhenius acid usually contains a hydrogen atom bonded to a chemical structure that is still energetically favorable after loss of H+. Aqueous Arrhenius acids have characteristic properties that provide a practical description of an acid. Acids form aqueous solutions with a sour taste, can turn blue litmus red, and react with bases and certain metals (like calcium) to form salts. The word ''acid'' is derived from the Latin , meaning 'sour'. An aqueous solution of an acid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Litmus Paper
Litmus is a water-soluble mixture of different dyes extracted from lichens. It is often absorbed onto filter paper to produce one of the oldest forms of pH indicator, used to test materials for acidity. In an acidic medium, blue litmus paper turns red, while in a basic or alkaline medium, red litmus paper turns blue. In short, it is a dye and indicator which is used to place substances on a pH scale. History The word "litmus" comes from the Old Norse word "litmosi" meaning "colour moss" or "colouring moss". The word is attested only in one Mediaeval source, a Norwegian law codex from 1316 in a chapter on customs and excise duties on pelts and furs. About 1300, the Spanish physician Arnaldus de Villa Nova began using litmus to study acids and bases. From the 16th century onwards, the blue dye was extracted from some lichens, especially in the Netherlands. Natural sources Litmus can be found in many different species of lichens. The dyes are extracted from such speci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dendrographa Leucophoea
''Dendrographa'' is a genus of lichen-forming fungi in the family Roccellaceae. It has seven species. These lichens form small, shrubby tufts that cling to bark or coastal rocks along the Pacific seaboard, with brown-grey main branches and paler, pencil-thin tips that lack a protective outer skin. The genus was originally established in 1895 for a single Pacific coast species, but molecular studies in the 2010s expanded it by transferring four additional species from other genera and led to the discovery of a seventh species in Brazil. Taxonomy The genus ''Dendrographa'' was circumscribed by the British lichenologist Otto Vernon Darbishire in 1895 to accommodate the distinctive Pacific-coast lichen then known as ''Roccella leucophaea''; Darbishire recognised that its fruticose habit, branch tips and calcium oxalate-encrusted medulla set it apart from ''Roccella'' and related genera. He therefore transferred the species as ''Dendrographa leucophaea'' and designated it the typ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Roccella Montagnei
''Roccella'' is a genus of 23 species of lichens in the family Roccellaceae. The genus was circumscribed by Swiss botanist Augustin Pyramus de Candolle in 1805, with '' Roccella fuciformis'' as the type species. Description ''Roccella'' presents a fruticose (shrub-like), thallus that is either erect or (hanging) with sparse branching. The main and terminal , varying in shape from flattened to rounded (), typically measure 2 to 5 mm (up to 10 mm) in thickness and 5 to 15 cm in length. These branches has colours ranging from creamy white-greyish to greyish-brown and have surfaces that are either smooth or wrinkled, with some being sparsely (powdery) or lacking pruina (epruinose). Soredia, reproductive propagules for asexual reproduction, are present in many species within the genus. The of ''Roccella'' lichens is made of hyphae that are arranged in an manner and are about 40 to 70 μm thick. The medulla (the inner layer) is loosely structured above, havi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parmelia (lichen)
''Parmelia'' is a genus of medium to large foliose (leafy) lichens.Field Guide to California Lichens, Stephen Sharnoff, Yale University Press, 2014, It has a global distribution, extending from the ArcticSkult H (1985) A New Subspecies of ''Parmelia omphalodes'' Ascomycetes Described from the Arctic. Annales Botanici Fennici 22, 201-6. to the Antarctic continentD.C. Lindsay (1973) Notes on Antarctic lichens: IV. The genera ''Cetraria'' Hoffm., ''Hypogymnia'' (Nyl.) Nyl., ''Menegazzia'' Massal, ''Parmelia'' Ach. and ''Platismatia'' Culb. et Culb. British Antarctic Survey Bulletin 36, 105-114. but concentrated in temperate regions. There are about 40 species in ''Parmelia''. In recent decades, the once large genus ''Parmelia'' has been divided into a number of smaller genera according to thallus morphology and phylogenetic relatedness. It is a foliaceous lichen, resembling a leaf in shape. The ends of the leaf-like lobes are often squarish-tipped. The upper surface is pale bluis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parmotrema Tinctorum
''Parmotrema tinctorum'' is a lichen which belongs to the ''Parmotrema ''Parmotrema'' is a genus of lichen belonging to the family Parmeliaceae. It is a large genus, containing an estimated 300 species, with a centre of diversity in subtropical regions of South America and the Pacific Islands. Members of the genus ...'' genus. The lichen is as known as the Palm Ruffle Lichen and is listed as secure by the Nature Conservatory. Description Grows to around 3–30 cm in diameter with board dull smooth slightly shiny gray lobes that are 10–20 mm wide. The underside is black with naked brown areas with a central collection of simple rhizines. Habitat and range Global distribution with a majority of samples being located in North America and Europe. Chemistry Compounds derived from Parmotrema tinctorum have been found to have anti-cancer properties. Environmental monitoring Parmotrema tinctorum has been identified and used as a candidate for monitoring air polluti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
